The Periodic Table and Ionic Bonding: Part 3-Periodic Table Trends 1

Objectives -Describe what properties metals have, and how metallic trends are shown in the periodic table -Explain what affects the size of atoms and how atomic radius trends are shown in the periodic table 2

Periodic Trend #1: Metals vs. Non-metals Metallic- able to lose electrons DOWN GROUPS, elements become MORE metallic –electrons are further from pull of positive protons so lost easier = conduct electricity ACROSS PERIODS, elements become LESS metallic –More protons so more attraction –Gain more electrons and becoming more stable and less likely to lose electrons

Periodic Trend #1: Metallic Properties

Periodic Trend #2: Atom Size 2 things affect the size of atoms: –1. Number of electrons (the more electrons, the bigger the atom) –2. Number of protons (more protons more attraction to electrons and decreases the size) These two statements contradict each other so which one is correct?

ACROSS PERIODS atoms DECREASE in size as electrons are being added to the same energy level (reason #2 is dominant over #1) ATOM Na Mg Al S P S Cl Ar SIZE (radius in Å= 1 x m) Periodic Trend #2: Atom Size

DOWN GROUPS atoms INCREASE in size as the electrons go into a higher energy level (get farther away from the nucleus) (Reason #1 above is dominant over #2) ATOM SIZE (radius in Å) H.32 Li 1.23 Na 1.54 K 2.03 Rb 2.16 Cs 2.35 Periodic Trend #2: Atom Size

Objectives -Describe what properties metals have, and how metallic trends are shown in the periodic table -Explain what affects the size of atoms and how atomic radius trends are shown in the periodic table 9